7.2 Current sensitivity/vulnerability

A frequent objective of human societies is to reduce their sensitivity to weather and climate, for example, by controlling the climate in buildings within which people live, shop and work or by controlling the channels and flows of rivers or the configurations of sea coasts. Recent experience with weather variability, however, reminds us that - at least at feasible levels of investment and technological development - human control over climate-related aspects of nature can be limited (see Box 7.4).

In fact, sensitivities of human systems to climate and climate change abound:

1. Environmental quality is a case in point, where weather and climate can affect air and water pollution and, in cases of extreme events, exposures to wastes that are hazardous to health. Consider the interaction between the ambient air temperature of an urban area and its concentration of ozone, which can have adverse health implications (Hogrefe et al., 2004; Section 7.4.2.4; Chapter 8), or effects of hurricane flooding on exposures to health threats (Marris, 2005).

2. Linkage systems, such as transportation and transmission systems for industry and settlements (e.g., water, food supply, energy, information systems and waste disposal), are important in delivering ecosystem and other services to support human well-being, and can be subject to climate-related extreme events such as floods, landslides, fire and severe storms. Such exposed infrastructures as bridges and electricity transmission networks are especially vulnerable, as in the experience of Hurricane Georges in 1998, which threatened port and oil storage facilities in the Dominican Republic (REC, 2004), or the 2005 experience with Hurricane Katrina (Box 7.4; Section 7.4.2.3).

3. Other physical infrastructures can be affected by weather and climate as well. For example, the rate of deterioration of external shells of building structures is weather-related, depending on the materials used, and buildings are affected by water-logging related to precipitation patterns. Another kind of impact is on demands for physical infrastructures; for instance, demands for water supplies and energy supplies related to temperature.

4. Social systems are also vulnerable, especially to extreme events (e.g., Box 7.1). Storms and floods can damage homes and other shelters and disrupt social networks and means to sustain livelihoods; and risks of such impacts shape structures for emergency preparedness, especially where impacted populations have a strong influence on policy-making. Climate is related to the quality of life in complex ways, including recreational patterns, and changes in temperature and humidity can change health care challenges and requirements (Chapter 8). For instance, it has been estimated that of the 131 million people affected by natural disasters in Asia in 2004, 97% were affected by weather-related disasters. Exposures in highly-populated coastal and riverine areas and small island nations have been especially significant (ADRC et al., 2005). Moreover, some references suggest relationships between weather and climate on the one hand and social stresses on the other, especially in urban areas where the poor lack access to climate-controlled shelters (e.g., the term ‘long, hot summers’ associated in the 1960s in the United States with summer urban riots; also see Arsenault, 1984 and Box 7.1). In some cases, tolerance for climatic variation is limited, for example in tightly-coupled urban systems where low capacity drinking water systems have limited resilience in the face of drought or population growth, not only in developing countries but also in industrialised countries. Another case is the sensitivity of energy production to heatwaves and drought (Box 7.1; Section 7.4.2.1).

Box 7.1. Impacts of the 2003 heatwave in Europe

The Summer 2003 heatwave in Western Europe affected settlements and economic services in a variety of ways. Economically, this extreme weather event created stress on health, water supplies, food storage and energy systems. In France, electricity became scarce, construction productivity fell, and the cold storage systems of 25-30% of all food-related establishments were found to be inadequate (Létard et al., 2004). The punctuality of the French railways fell to 77%, from 87% twelve months previously, incurring ¤1 to ¤3 million (US$1.25 to 3.75 million) in additional compensation payments, an increase of 7-20% compared with the usual annual total. Sales of clothing were 8.9% lower than usual in August, but sales of bottled water increased by 18%, and of ice cream by 14%. The tourist industry in Northern France benefited, but in the South it suffered (Létard et al., 2004).

Impacts of the heatwave were mainly health- and health-service related (see Chapter 8); but they were also associated with settlement and social conditions, from inadequate climate conditioning in buildings to the fact that many of the dead were elderly people, left alone while their families were on vacation. Electricity demand increased with the high heat levels; but electricity production was undermined by the facts that the temperature of rivers rose, reducing the cooling efficiency of thermal power plants (conventional and nuclear) and that flows of rivers were diminished; six power plants were shut down completely (Létard et al., 2004). If the heatwave had continued, as much as 30% of national power production would have been at risk (Létard et al., 2004). The crisis illustrated how infrastructure can be unable to deal with complex, relatively sudden environmental challenges (Lagadec, 2004).

5. Climate can be a factor in an area’s comparative advantage for economic production and growth. Climate affects some of an area’s assets for economic production and services, from agricultural and fibre products (Chapter 5) to tourist attractions. Climate also affects costs of business operation, e.g., costs of climate control in office, production and storage buildings. Not only can climate affect an area’s own economic patterns; it can also affect the competitive position of its markets and competitors, and thus affect prospects for local employment and individual livelihoods. Many workers are ‘marginal’, whose livelihoods can be especially sensitive to any changes in conditions affecting local economies.

6. Impacts of climate on industry, settlements and society can be either direct or indirect. For instance, temperature increases can affect air pollutant concentrations in urban areas, which in turn change exposures to respiratory problems in the population, which then impact health care systems (Chapter 8). Tropical storms can affect the livelihoods and economies of coastal communities through effects on coral reefs, mangroves and other coastal ecosystems (Adger et al., 2005a). Tracing out such second, third, and higher-order indirect impacts, especially in advance, is a significant challenge.

7. Impacts are not equally experienced by every portion of an industrial structure or a population. Some industrial sectors and the very young, the very old and the very poor tend to be more vulnerable to climate impacts than the general economy and population (Box 7.1; Section 7.4.2.5). Some of these differences are also regional, more problematic in developing regions and intricately related to development processes (ISDR, 2004).

Current sensitivities to climate change are briefly summarised in Chapter 1 of this Fourth Assessment Report, and in a number of cases they are relevant for the Millennium Development Goals (for a brief discussion of MDGs in the context of possible climate-change impacts on industry, settlement and society see Section 7.6; also Chapter 20).

Tourism is an example of an economic sector where there has been substantial recent research to understand its sensitivity to climate (Besancenot, 1989; Gomez-Martin, 2005); the emphasis on climate change is, however, more recent (Scott et al., 2005a, b). For example, travel decisions are often based on a desire for warm and sunny environments, while winter tourism builds on expectations of snow and snow-covered landscapes (Chapter 14, Section 14.4.7; Chapter 12, Section 12.4.9; Chapter 11, Section 11.4.9). Tourism is thus sensitive to a range of climate variables such as temperature, hours of sunshine, precipitation, humidity, and storm intensity and frequency (Matzarakis and de Frietas, 2001; Matzarakis et al., 2004), along with the consequences that may follow, such as fires, floods, landslides, coastal erosion and disease outbreaks.